Process for the manufacture of asphalt.



c. B. FORWARD.

PROCESS FOR THE MANUFACTURE OF ASPHALT.

Patented July 18, 1911.

APPLICATION FILED JULY 11,1910.

D m mm rm n mm m C ATTEST I 744. 5*

BY ATTV8 UNITED STATES PATENT oFrIoE.

v CHAUNGEY B. FORWARD, OF URBANA, OHIO.

PROCESS FOR THE MANUFACTURE ASPHALT.

Specification of Letters Patent.

Patented Jul 18,1911.

Application filed July 11, 1910. Serial No. 571,293.

To all whom it may concern:

Be-it known that I, CHAUNonY B. Fon- WARD, citizen of the United States,residing at Urbana, in the county of Champaign and State of Ohio, haveinvented certain new and useful Improvements in Processes for theManufacture of Asphalt, of which the following is a specification. I

My invention relates to a process for the manufacture of asphalt frompetroleum residuum or from crude petroleum from which the lighter oilshave been removed and the residuum remains.

It is well known that in various fields throughout the world vary ingravity, consistency and value according ,to the quantity and quality ofthe distillates derived therefrom. lVe have the so-called 'parafiin baseoils of Ohio, Pennsylvania, and other States or sections, and theasphalt base oils of Texas, California, and elsewhere, as well known. Ihave in a satisfactory way demonstrated that asphalt is in reality thebase of all the so-called paraflin base oils, and have made a superiorgrade of asphalt suitable for paving, roofi'ng and insulating and infact anything for which the natural asphalt can be usedfrom thismaterial. In fact I have made these from almost every known oil fieldinthe world, and the product cannot be distinguished from natural asphaltby any method now known to the most scientific chemists.

In handling the crude oil, or residuum, in a commercial way for theproduction of asphalt, I first try out a small quantity of residuum, sayabout a "gallon, in an open vessel and subject the same to a temperatureof about 625 F. I have found by experience that this temperature isbelow the coking point, but I do not wish to. be understood as claimingthat this is the only temperature which, if maintained, could accomplish the desired result, as the same product can be secured at alower temperature, say 550 to 575 F., but it would re quire much longerto accomplish the same end. The point to be observed is to keep it belowthe coking point which destroys the value of the resultant product.lighter oils can be removed much more rapidly in an open vessel than ina closed re- .tort or still. The asphalts to be usedfor roofing orpaving or insulating or as a base for paints and so forth are all of adifferent consistency, and I stop my process when the the oils producedThe I I wish to remove from a quantity of crude oil or residuum tocommence with, I prodeed to make it inlarge quantities or on acommerc1al scale 1n the following manner,

-As the first step I place the petroleum residuum 1n a retort indicatedby R in the accompanying diagrammatic drawing. If there be considerablemoisture in the stock I subject it to a temperature of about 175.degrees F. At this temperature the moisture will precipitate as waterand can be drawn ofl? from the bottom of the retort through a suitableopening or pipe 4:, Fig.

4, for that purpose. If, however, there 1s but a small amount ofmoisture present I put the temperature up -to 24:0 to 250 degrees F.,and in the course of an hour and a half to two hours at this temperaturethe moisture will have all been evaporated. If I allow the temperatureto rise to 400 or 500 F. before the moisture, has been removed theresiduum will foam and 'be forced out through the worm end of theretort. After all the moisture is driven off I increase the temperatureto 625 F. and continue to subject it to this heat for a period oftwentyfour to forty-eight or even up to sixtyhours according tothegravity of the residuum originally started with. The lower thegravity the less time it will take to distil off the lighter products.The exact time of subjecting it to the temperature of .625 F. has to bedetermined in each instance by experivment with the residuums ofdifferent gravities. After the expiration of about thirtysix to-fortyeight hours at this temperature l commence to test the resultantmaterial in the'retort by withdrawing a small quantity of it from timeto time through a suitin to the purpose for which it is being miide up,I shut off the fire and withdraw *the material to an open pan or vessel,-not shown, for reasons hereinafter set forth, and

allow it to be there subjected to a temperature of about 100 degrees F.less than it was' in the still for a period of fiveto twentyfour hoursaccording to the product I wish to vacquire, such as hard, semi-hardora.

thick liquid asphalt.

Now, as to the object and advantage of drawing the material off into anopen vessel, I have discovered that if the process of distillation iscontinued in a closed still until the remaining product therein is ofthe proper degree of hardness (when cold) the product will not have thejet black luster of natural asphalt, but will be of a bluish cast and infact will exhibit nearly, if not all, the colors of the rainbow and thematerial will not have the desired degree of toughness, or, in otherwords, will not have the desired adhesive, cohesive and lastingqualities. I have demonstrated this time and time again by continuingthe process of distillation in the closed still, and I have found thatit is impossible to get the quality'of material I make except by theadditional use of the open vessel. The product left in the still can ofcourse be reduced to a semihard or hardpitch by continuing it therein,

but, as above stated, the resultant product will not have the properadhesive, cohesive and lasting qualities, and when the process in thestill is carried far enough to make a pitch of a quality and hardnesssuitable for paints, for. instance, I find it has not the jetblackluster, but has a bluish cast and is varicolored, and itwill not retaineven this luster but will disintegrate and take on a dull blackappearance in a short time when exposed to the atmosphere. Inendeavoring to make a softer grade suitable for paving or roofingpurposes, I find it impossible to perfect the product in'the closedstill as it will lack the distinctly characteristic qualities abovementioned and will disintegrate when of asphalt by so doing than when Idraw "it off in the open vessel.

After delivering the material in' an open vessel I subject it to atemperatureof about 100 degrees Eless than it-was in the closed still,and this heat is nots'ufiicient to driveoff any additional oils' by:vaporization. The

exposure of the"product-in the open vessel at about this temperature hasthe effect of driving off some fixed gases but does not I substantiallylessen the material in weight, and throu h this exposure the materialacquires the %lack luster of the refined natural asphalt and anadditional degree of hardness or toughness with its adhesive, cohesiveand lasting qualities which are lacking if the attempt be made to finishthe material in the closed still.

The time for exposure in the open vessel varies according to the qualitydesired in the finished product which I am working to obtain. If I ammaking a soft liquid asphalt, five to eight hours in the open vessel issufiicient although a longer exposure would not be detrimental. But fiveto eight hours is sufiicient making the liquid asphalt to be used. asaflux for the natural asphalt or any purpose for which such a flux canbe used, If I desire a paving or roofing material I treat it in the openvessel for fifteen to eighteen hours, and if a harder material iswanted, such as is used as a base for paints and varnishes, I subject itto twenty-four to twenty-eight hours treatment. I have found byexperience that the above time is sufficient in the open vessel in orderto acquirethe quality desired, but I do not wish it to be understoodthat any additional exposure would destroythe resultant product. Theseresults are not only accomplished by my invention as herein set forth'but thematerial so made cannot be distin guished from the naturalasphalt by any expert chemist.

There is manifestly no hard and fast rule to be laid down as to theexact number of hours, either in the closed still or in the'open vessel,as I am starting, possibly, each time with a residuum or oil ofdifferent gravity and character and may be working to get a differentproduct at the finish according to thedemand the market is calling forat that time. However, by reducing a small quan tity, say a gallon, inan open vessel to commence with as originally described, I can thenreadily determine how long to subject the larger quantity in'the closedstill and open pan according to the product I am starting with and theconsistency of the product I desire to make, my previous work' with thesmall quantity enabling me to know just how much of the lighter or morevolatile portions I want to take off when I am working with a largeramount. This of course can only be done by those who are accustomed tohandling the product and lmow the end that they desire to accomplish.Experience alone will teach them.

- A product for paving or roofing purposes would be of the'consistencyof chewlng gum. That is, by removing a sample I determine by chewing itwhen it has arrived at the proper stage When you can string it and pullit likegum and it does not disintegrate and stick to the teeth it isready for the market. To make the asphalt product harder it is simplynecessary to subject it to the aforesaid temperature 625 F. for a longerperiod, dependingon the gravity of the product originally started wi Ikeep on testing it from time to time until it has acquired the fulldegree of hardness that I desire. The very hard product is a verysuitable base for asphalt paints and varnishes. The product between thehard and soft chewable material above mentioned is valuable forinsulating purposes or for all purposes for which an insulating compoundforty-eight hours, and during that period before stated below the cokingpoint.

there is no appreciable loss of material by weight though somegasesdoubtless will be given off. The resultant product is an admirable fluxto bring natural asphalt to a consistency for paving or roofing purposesor for the laying of dust on unpaved streets or ainy other purpose forwhich itmight be use In subjecting the residuum to a temperature of 625F. the heavy paraflin oils contained therein will be vaporized andcarried olf by the aid of superheated steam or compressed a1r accordingto which of the two is used, and will'be condensed and caught in theoutlet tanks numbered 1, 2 and 3, respectively, according to gravity.That taken from the opening nearest the retort is of course the lowestgravity, as the lower gravity oils will condense at a much higherterrierature than the higher oils, and that the arthest away thelightest or hi best. A suit-able overflow or escape pipe 6 as adistended end or receiving mouth over the still and leads by successivedown pipes 7 to tanks 1, 2 and 3.

I have found by experience that the product in the retort will not cokeat a temperature of 6'25 F. and in order to get the. asphalt as aproduct of such value as I require 1t is necessary-to keepthetemperature as But the vapors of the heavy parafiin oils willnot passout from the retort into the said tanks at so low a temperature withoutassistance and hence I employ su erheated' steam or air as auxiliarymeans or this purpose. I say'superheated, or at least heated to such adegree that the va ors will be carried out thereby and for-war densingtanks according to their ravity. Otherwise, or without such aid theeavier vapors would not be or become sufficiently into the severalconvolatile to float away, and a lower temperature of either steam orair would rather tend to chill and condense said vapors, particu-' larlybecause the heavy paraflin oil I desire to eliminate condenses at a veryhigh temperature.

In introducing the superheated steam orair into the still I have theinflow pipes placed at a'point above the surface of the oil or residuumas the case maybe and all the openings in the pipe, which shouldcompletely encircle the still, point toward the outlet or overflowprovided for the escape of the vapor.

The foregoing description and process obviously deal with a condition inthe retort which renders outside aid necessary for the reason that if atemperature be employed in the retort itselfhigh enough to expel allvolatilizable constituents it will coke the material or make it .of novalue for asphalt,

and if a lower temperature than say 625 F.

be used, as described, the said constituents will simply condense andfall back into the material in the retort and the process will dertreatment be derived in the still from crude petroleum or he brought toit as a residuum from treatment elsewhere or under different conditions.Hence the value of su plemental means or agencies for getting ri of thevapors in the still in a manner fail. This is true whether'the materialunwhich does notsenter ihto or agitate the mass in the still but is deivered over the same and with a sustained pressure of about forty-fivepounds tov the inch, which ressure or movement simply forces the saivapor forward, into the condensing and rece tacles rovided there. e thusrecover all the oi s of heavy gravity (which are valuable)i so thatthere is practically no appreciable oss in quantity of material fromthat originally started with.

Asshown in the drawings I have a plant employing compressed air storedin a tank or vessel A, a heating coil C with a gas assages burner Btoheat the same'and from which coil the su erheated or highly heated airis drawn un er a considerable ressure into the annular distributing pipein retort B.

By the word residuum as herein employed I mean the product remaining ina still after the crude oil has been subjected therein to the processesof distillation as commonly practiced by all refiners of crude oil. Thisproduct is well known on the market as petroleum residuum or petroleumtar.

This residuum may vary in gravity from seventeen degrees Baum totwentyto twentv-two'degrees Baum, more or less, depending altogether on thechar'acter'of the crude petroleum originallyplaced in the still, andalso on the quantity and quality of the distillate that the refinerdesiresto take. from the crude. By way ofv illustratar of a gravity fromtwenty to twenty-two degrees Baum. Should-due have a "market at the timefor the heavier grades of paraflin oils he will carry the process ofdistil lation still farther and take oflthe heavier paraffin oils and hewill'then have left-in his still a residuum or tar of a gravity fromseventeen to nineteen' degrees Baum.-

It is obvious then that when I start to.

make asphalt from a residuum of twenty to twenty-two degrees gravity, itwill take longer than if I had started with the seven teen to nineteendegrees gravity tar, as the heavy paraffin oils have already beenremoved-from the seventeen to nineteen degrees gravity tar before Icommence opera- .tions, and when'I start with the twenty to twenty-twodegrees gravity, I have to take the time necessary to remove these heavyoils by distillation. The residuum or tar of seventeen to nineteengravity still contains a quantity of the very heavy oils which must beremoved to make my product, asphalt. I remove these heavier products vatlower temperature and below the cokrag point by the use of superheatedair or steam, air being preferable, as that avoids the necessity of theseparation of distillate from the water (condensed steam), which isrequired to bring over the vapors at the temperature which I applyiWhile I may start wzth the tar or residuum from the so-called paraflinbase oils, the process is justas applicable to the so- -called asphaltbase oils, the only difference being that the residuum or tar wouldi bethe productleft int-he still after the heavy lubricating or cylinderoils have been removed from the crude oil by previous dis tillationinstead of the heavy parafiin oils.

.W'hile thisheavy lubricating oil in a way correspond with theheavyparaflin oil, it is much lower in gravity and ofcourse does notcontain the parafiin. However, in dealing with the so-calledasphaltbase-oils this heavy low gravity lubricant must be removed fromthe-crude oil or tar case may be before-I can get-my product, as phalt.The same is true 0 ther-so ea'lled' asphalt base oils as of theso-called paraflin base oils. If the refiner oils had no market at thetime forthe heavy low gravity lubricant, he would stop his process ofdistillation when the lighter lubricants had been removed, andhisresiduof the asphalt base" ceases um would then ,be'ofmuchhighergravity than if he continued his process of distillation until the heavylubricants had been removed, If, therefore, I started to make asphaltfrom residuum ortar from the s0 called asphalt base oils, it is againobvious that it would require more time to make it from the residuumfrom which only the lighter lubricants had been removed than- M from theresiduum where the heavier lubricants had also been removed by previousdistillation. It can, therefore, be readily seen that my; process. formaking asphalt could just as well start from the crude oil as from theresiduum or tar, the only point being .the'longer time necessary to takeoff the lighter oils before getting down to the residuum or ten. I

What I claim is:

.1. The method herein described of making asphalt from petroleumresiduum, which consists, first, in subjecting the same to a temperatureof approximately 625 F. in a vessel until substantially all thevolatilizablesubstances are driven off and then drawing the material offinto an open vessel and boiling the same therein at a temperatureconsiderably below 625 F. as explained and for a period dependent on thequality of the product desired. v

2. The method herein described of making asphalt from petroleum residuumwhich consists insubjecting the residuum to a heating process in avessel having a free discharge for the vapors at a temperatureapproaching a coking heat and at the same time injecting a fluid such assteam or air, into the vessel over the material therein and at atemperature high enough to carry off the vapors liberated in the boilingoperation, thereby ridding the residuum of oil, and, lastly, boiling thematerial remaining in an open vessel for a brief period at a temperatureofapprom'mately 400 to 500 F. 3. The method herein described of makingasphalt from petroleum, residuum which consists in subjecting theresiduum to a heating process at a temperature of approximately 625 F.in a vessel until the volatilizable su'bstancesare driven off and at thesame time applying superheated steam or air under pressure next above orover said residuum and thereby carry off the vapors liberated from theresiduum so treated and then subjecting the residuum to a heatingprocess in an open-vessel as described.

Intestimony whereof I affix my signature in presence of two witnesses; i

CHAUNOEY B. FORWARD. Witnesses:

E. M. Frsmnc, F. 'C. MUssuN.

